Radiation therapy involves medical procedures that selectively expose certain areas of a human body, such as cancerous tumors, to doses of radiation. The purpose of the radiation therapy is to irradiate the targeted biological tissue such that undesirable tissue is destroyed. Radiation has also been used to obtain images of tissues for planning or treatment purposes.
During a radiation planning session, radiation treatment planning is performed before treatment radiation is delivered to a patient. This allows an accurate and precise dosage of radiation to be delivered to a patient. During the planning session, configuration data, such as location, size, and shape of a target object, may be acquired from an imaging procedure. Such imaging procedure may be performed using existing CT imaging systems. Existing CT imaging systems are configured to take image slices of the patient in which the image slices are vertical (or perpendicular to a longitudinal axis of the patient or patient support). However, in some cases, it may be desirable to take image slices that are non-vertical or non-perpendicular to the longitudinal axis of the patient or the patient support. Another problem associated with existing imaging systems is that use of such systems generally requires the patient to be supported and oriented horizontally. However, in some cases, a patient may not feel comfortable resting horizontally (as in the case with emphysema patients), or may not physically lay flat horizontally due to an injury or illness.
After the radiation treatment plan is determined, the patient then undergoes a radiation treatment procedure. During a radiation treatment procedure, a radiation treatment system is used to deliver a desired radiation dosage to the patient according to the determined radiation treatment plan. In existing radiation treatment systems, the radiation source that generates the radiation beam is configured to rotate within a plane that is substantially vertical (or perpendicular to a longitudinal axis of the patient or the patient support). Varying the intensity and the entry angle of the incident radiation beam allows a radiation specialist to generate a radiation dose volume that corresponds to the size, shape, and location of the target region. However, in some cases, it may be desirable to deliver radiation beams that do not lie within a vertical plane. Also, it may be desirable to deliver radiation beams that lie in a plurality of planes (which may or may not include a vertical plane). Further, as in the case with the imaging procedure, in the treatment procedure, a patient may not feel comfortable resting horizontally (as in the case with emphysema patients), or may not physically lay flat horizontally due to an injury or illness.